I have a question about how to decompose a unitary quantum gate in a currently existing simulator or emulator. I have read some papers about SK algorithm and other algorithms which aim to decompose unitary quantum gates. Is there any specific method to decompose a quantum gate in a currently existing simulator? Some papers about decomposition methods mention Trotter-Suzuki decomposition but I don't exactly know if this is true? To be more specific, what is the decomposition algorithm in Qiskit or Project Q?
In Qiskit, the iso() function allows you to add a gate, defined by means of a unitary, to your quantum circuit:
The decomposition used in the iso() function was introduced by Iten et al. in https://arxiv.org/abs/1501.06911.
Of course this is related to the circuit, not to the backend (which can be real or simulated).